As a common method of preparing 3D stereoscopic photographs using a lenticular sheet, an indirect method is generally employed. In this method, a deep focused object is photographed with a camera charged with a normal film while the camera is moved horizontally or arcuately by a predetermined distance to prepare a plurality of negatives which contain images photographed with different angles. In these negatives, the position of images is shifted with each other in accordance with the distance between the camera and the object. Instead of taking photographs while a camera is moved, it is also possible to use a camera which contains a plurality of lenses aligned horizontally or a plurality of horizontally disposed cameras, to effect a simultaneous photographing to obtain a plurality of negatives. Although the number of the negatives is not particularly limited, it is generally 3 to 5.
In the indirect method, a plurality of negatives obtained as above are exposed on a photosensitive sheet composed of a lenticular sheet and a sensitized material applied onto the flat face of the lenticular sheet. The exposure is conducted in such a manner that the negatives are exposed by the use of an ordinary projection lens but with different projection angles to form images on the photosensitive sheet. When an image of a negative is projected onto the photosensitive sheet, the image is divided parallel to the axis of the lenticular lenses in the photosensitive sheet and compressed into a line. The projected image forms discrete and compressed line images on the sensitized layer of the back face of the lenticular lens sheet. Thereafter, the next adjacent negative is exposed under the condition where the relative position between the projection lens and photosensitive sheet is changed so as to form a new line image juxtaposed with the previously formed line image. This process is repeated to fill the entire back face of the lenticular lenses widthwise with line images originated from different negatives. Thus, images of a plurality of negatives can be printed on a piece of photosensitive sheet. A plurality of exposures may be simultaneously conducted using a multiple projection lenses.
When the exposed photosensitive sheet is developed and looked at from the lenticular lenses' side, the line images formed in the sensitized layer are enlarged widthwise so that we can see a restored image. If a person looks at the developed lenticular sheet at a specific distance from his or her eyes, the right and the left eyes can receive different images adjacent to each other, and the two separate pieces of visual information are combined in his or her brain to achieve a stereoscopic viewing.
As described above, in order to obtain a single stereoscopic photograph, a plurality of exposures are required while changing the projection angle. FIG. 1 shows a perspective view of a conventional printing/developing apparatus for 3D stereoscopic photographs. A required projection angle is obtained by a movably disposed exposure stage and a movably disposed lens unit. To secure free movement of the exposure stage and the lens unit, a rolled printing paper conveyed by a set of rollers is first cut into pieces of sheet by a cutter and then fed to the exposure stage. Paper chips generated at the time of cutting of the roll paper may have a detrimental effect on exposure, and therefore, they are eliminated by vacuum or the like. Thus, the cutting section for a rolled printing paper comprises a cutter and a paper chips disposing unit.
In the processing of 3D stereoscopic photographs, sheets of printing paper are manually developed by the use of a printing/developing apparatus for this specific purpose of producing 3D photos equipped with a movable lens unit and a movable exposure stage. In the area of producing ordinary photographs, especially for producing very common, so-called service prints or providing services of simple enlargement, printing/developing apparatuses equipped with a fixed set of lenses, a fixed exposure stage, and means for developing and drying are frequently used, and a rolled printing paper is developed as is before cut into sheets at the final stage of the process. In the production of ordinary photographs, however, if trimming is specifically ordered, manual procedure of development is followed and a specialized printing/developing apparatus equipped with a movable lens unit and a movable exposure stage is used.
In the field of printing/developing apparatus for photographs, speed-up of processing is required as well as improved image qualities and long life of image qualities. As a result of efforts for improving the efficiency in the processing performance of printing/developing apparatus, and also as a result of using highly sensitive printing papers carrying a thin layer of emulsion, time required for the steps of exposure, development and drying has become shortened. On the other hand, a variety of consumers' needs including increased needs for the special size photographs such as panorama photos have resulted in the presence of various standards of photos. Thus, it remains a pressing need in the industry to provide a printing/developing apparatus which meets the requirements of various standards.
Having regard to the physical form of printing papers in the course of being transported in a printing/developing apparatus, there are two forms; one is a sheet and the other is a roll. Several problems are found, as discussed below, in a developing process in which a printing paper is fed as sheets, as compared with the case in which a printing paper is fed in a roll-form without being cut.
Cutting a rolled printing paper into sheets inevitably adds an extra interval before the exposure process, and this will result in a decrease in processing efficiency. Additionally, it will add the complexity to processing of paper chips and a need for extra maintenance of the apparatus, and the apparatus tends to become larger since both a cutter and a paper chip disposing unit must be mounted in front of the exposure stage composed of an intricate driving mechanism. The processing efficiency of sheets of paper in a developing process also becomes lower than that of a roll paper.
The transporting mechanism for sheets of paper has to be composed of many transporting rollers. Such rollers must be installed at intervals at least shorter than the length of a sheet of paper. These transporting mechanisms are illustrated in FIGS. 2 and 3. The transporting path of a printing paper is shown by bold arrows in each Figure. FIG. 2 is a cross-sectional view of a transporting mechanism for sheets of paper, while FIG. 3 is that for a roll paper.
As shown in FIG. 2, when the transporting path of sheets of printing paper is composed of complicated curves, it requires a particularly large number of transporting rollers 9, and that leads to the difficulty of securing room for a guide 13. The loading edge of sheets of printing paper is apt to be diverted from the transporting path and tends to cause a paper jam in the transporting path. By contrast, as illustrated in FIG. 3, the transportation of a rolled printing paper requires only a small number of rollers 11, and in addition, it rarely suffers a paper jam because the transporting path is directed by a guide 15.
In view of these problems, a rolled printing paper is assumed to be more advantageous in the aspects of processing efficiency and simplification of the apparatus. However, it is difficult to apply it to a printing/developing apparatus for stereoscopic photographs because the exposure stage and the lens must be movable to accommodate multiple exposures for a single picture while changing projection angles. In other words, the adoption of a rolled paper-transporting system in a printing/developing apparatus for stereoscopic photographs adds limitations to the movement of the exposure stage. In addition, it is also difficult to apply it to a printing/developing apparatus for ordinary photographs in which trimming will be performed, because the exposure stage, etc. must be movable. The present invention, therefore, intends to encompass a printing/developing apparatus capable of transporting a rolled printing paper, aiming at improvements in the processing efficiency and simplification of the apparatus.